Process for manufacturing 1.8-naphthoxypenthiophen compounds



Patented Apr. 16, 1929.

I UNITED STATES PATENT OFFICE.

JEJNS MULL R, or HAnAU-on-THE-M IN, AND MAX scanner, or FECHENHEIM,

NEAR FRANKFORT-ON-THE-MAIN, GERMANY, ASSIGNORS TO cnAssnLLI DYE- srnrr CORPORATION, OF NEW YORK, n. Y., a CORPORATION or DELAWARE.

r'noonss FOR MANUFACTURING 1.S-N P THOXYPnnrnrornnit eozcrounns.

No Drawing.

The hitherto known methods for preparing 1.8naphthoxypenthiophen f. i. by subjecting 1.8-1]aphthothioglycolic carbcxyhc acid to the alkali fushion (see Liebigs Annalen vol. 388, page 22) or by heating it with acetic'acid anhydride (see German Patent No. 198,050) are lacking in yield and purity of the product obtained and are also much too complicated 1Q technical scale.

'VVe have "found a new process which allows to produce on a technical scale l.8-naphth oxypenthiophen and its nuclear substitution products, which are valuable parent materials for the production of vat dyestuffs, in a pure state with an excellent yield. Our new process consists in heating the 1.8-naphthothioglycolic carboXylic acid and its nuclear substitution products in an aqueous solution or suspension in a closed vessel at temperatures greater than 150 and not substantially above 200 C. The addition of an electrolyte, such as sodium chloride is of an advantage.

The reaction runs probably according to the following equation (wherein the unsubstituted 1.8-naphthoxypenthiophen is taken as a specific example) III 1.8-naphthothiog-lycolic carboxylic acid 1.8-11aphthoxypenthiophen for the manufacture on a Application filed October 5, 1927, Serial No. 224,271, and in Germany Ccte'ner 153, 1926.

boxylic acid consists in introducing substituents into its molecule f. i. by halogenatron such as bromination- In order to further illustrate our invertion the following examples are given, the parts being by weight and all temperatures in tentigradc degrees, but it is understood, that our invention is not limited to the particular products or reacting conditions mentioned therein.

L acm-pZe 1.

150 parts of 1.S-naphthothioglycolic carboxylic acid and 2000 parts of water, to which preferably about 600 parts of common salt are added, are heater for some hours in an autoclave while stirring at 170-200 C. After cooling the l.8-naphthoxypenthiophcn is separated as a brownish crystalline precipitate which is filtered. t may be direct ly used in this form for technical purposes. One crystallization f. i. from ligroine pro duces it in a pure state, melting at 8485 C. as described in literature (cf. Liebigs Annalen, 1. 0.).

Example 2.

15 parts of monobromo-l.8-naphthothioglycolic carboxylic acid, prepared by treating a solution of 13 parts of the carboxylic acid in 200 parts of glacial acetic acid with a solution of 9 parts of bromine in 20 parts of glacial acetic acid in the cold and melting at 230 C. in a pure state, are heated while stirring for some hours in an autoclave with 200 parts of water to 170-180 C. After cooling down the resinous reaction product is filtered. For purifying it may be extracted with spirit, advantageously with addition of animal charcoal. From the filtrate the new monobromo-l.8-naphthoxypenthiophen is separated by adding water. It crystallizes from spirit as greenish yellow needles, melting at 130 C. It is soluble in concentrated sulfuric acid with a purple red color, turning to a dull brown while decomposing, easily soluble in chloroform and glacial acetic acid, less soluble in benzine and alcohol.

The pressure in the autoclave applied for our process corresponds functionally to the tension of the reacting agent and the temperature applied.

In the same manner other nuclear substitution products of 1.8-naphthoxypenthiophen may be obtained containing f. i. halogen nitro-, amino and alkoxy-groups in the nucleus.

In the following claims we include under the terms 1.8-naphthoxypenthiophen compounds and 1.8-naphthothioglycolic carboXylic acid compounds 1.8-naphthoxypenthiophen and 1.8-naphthothioglycolic carboxylic acid themselves respectively as Well as their nuclear substitution products.

o claim:

1. A process for manufacturing 1.8-naphthoxypenthiophen compounds which proc ess comprises heating an 1.8-naphthothioglycolic carboxylic acid compound in the presence of water at temperatures greater than 150 C. and not substantially above 200 C.

2. A process for manufacturing 1.8-naphthoxypenthiophen compounds which process comprises heating an 1.8-naphthothioglycolic carboxylic acid compound with a concentrated aqueous solution of an electro lyte at temperatures greater than 150 C. and not substantially above 200 C.

3. A process for manufacturing 1 S-naphthoxypenthiophen Which process comprises heating the 1.8-naplithothioglycolic carboxylic acid with a concentrated aqueous sodium chloride solution at temperatures greater greenish yellow needles, soluble in concene trated sulfuric acid with a purple red color, turning to a dull brown, while decomposing, easily soluble in chloroform and glacial acetic acid, less soluble in benzine and alcohol, which product is substantially identical with a compound obtainable byheating a monobromo 1.8 naphthothiog'lycolic carboxylic acid of the meltingpoint 230 C. in the presence of water at temperatures greater than 150 C. and .not substantially above 200 C.

In testimony whereof, We atliX our signatures.

J ENS MULLER. MAX SCHUBERT. 

